The Emad (Pillar) surface-to-surface missile, designed and built by Iranian experts, is the country's first long-range missile that can be precision-guided until it reaches its target, said Brig. Gen. Hossein Dehqan, Iran's defense minister.

Dehqan said following the launch that the Emad would greatly increase Iran's strategic deterrence capability, state media reported.

Improved accuracy

Anthony Cordesman, a researcher at the Center for Strategic and International Studies, wrote in October last year that the Emad was a variant of Iran's existing Shahab-3 long-range missile, "but with a maneuvering reentry vehicle to improve system accuracy and complicate missile defense."

The liquid-propelled rocket had a range of 1,700 kilometers (1,056 miles) and was accurate to within 500 meters (1,640 feet) of the target.

Cordesman's report said Tehran has been steadily developing its missile technology, focusing in particular on improvements to guidance systems.

Its existing missiles systems had "poor accuracy and uncertain reliability," he wrote, giving them limited military effectiveness.

The improving missile arsenal gave Tehran "a longer range strike capability that its aging air force largely lacks," he wrote.

Iran's air force, once the largest in the Gulf, degraded following the break with the West that occurred during the 1979 revolution, due to a lack of access to spare parts, maintenance and pilot training, according to Elleman.

Since then, Tehran has focused on developing its missile capability, and now boasts the "largest and most diverse ballistic missile arsenal in the Middle East," according to Elleman. Israel's stockpile was more capable, but smaller, he wrote.

'Dangerous threat'

Iran's missile program is being closely watched around the world, with Washington leading international efforts to stymie the growth of Tehran's arsenal.

When Tehran announced in February last year that it had successfully test-fired a laser-guided surface-to-surface and air-to-surface missile and a long-range ballistic missile capable of carrying multiple warheads, the Pentagon spokesman at the time, Adm. John Kirby, described the missile program as "a dangerous threat to the region."

He noted that U.N. Security Council Resolution 1929 prohibits Iran from undertaking any activity related to ballistic missiles capable of delivering nuclear weapons, including launches using ballistic missile technology.

Since 2003, concern over Iran's nuclear program has grown as Iran and the International Atomic Energy Agency spar over Iran's growing capability.

Iran's Supreme Leader Ayatollah Ali Khamenei has insisted Iran is not building a bomb and says weapons of mass destruction are forbidden under Islam.

In July, negotiators from Iran, the United States, China, Germany, France, Britain and Russia reached a deal on Iran's nuclear program, agreeing to reduce the number of Iranian centrifuges by two-thirds. The agreement bans enrichment at key facilities and limits uranium research and development to the Natanz facility.